Process and apparatus for controlling distribution of thread on a package in a collection unit for synthetic threads

Abstract

The present invention relates to a process for piloting the distribution of thread on a package under formation, in a collection unit for collecting synthetic threads, to prevent ribboning from forming during the continuous overlapping of different winding layers. The present invention further relates to an apparatus to implement the above process. The process comprises setting, instant by instant, values of operational parameters during the thread winding in such a way that the collection unit operates along descending portions of lines. Each line is defined by a constant and non-integer "winding ratio" "K". The line portions are contained inside a range bounded by a maximum threshold value and a minimum threshold value of the winding angle. The maximum and minimum threshold values are symmetrical to the optimum value. The process further relates to piloting a traverse cam to fix any dislocation of the descending line portions at a distance higher than, or at least equal to, a prefixed reference value.

We claim: 
     
       1. A process for winding thread from a spinning apparatus in sequential steps in a winding cycle onto a rotating spindle of a collection unit at a constant rate for forming a package, wherein the collection unit comprises a traversing device for reciprocatingly guiding the thread from the spinning apparatus along the longitudinal axis of the spindle, wherein the reciprocating speed of the traversing device decreases in proportion to the decrease in rotational speed of the spindle so that values of constant winding ratios are produced which define a series of operating lines and rapidly increasing the reciprocating speed of the traversing device at the end of each sequential step, wherein the process comprises: a) setting operating parameter values of winding angles for controlling the traversing device so that ribboning is not produced on the package, wherein said operating parameter values comprise a minimum value, an optimum value, and a maximum value wherein said minimum value and said maximum value are equidistant from said optimum value;   b) determining critical winding ratios defining lines from said set operating parameters wherein said critical winding ratios form undesirable packages having ribboning and determining said critical winding ratio lines closest one another;   c) setting a reference value not greater than half the distance between said critical winding ratio lines closest one another;   d) controlling and continually regulating the reciprocating speed of the traversing unit so that during each sequential step of the winding cycle, said series of operating lines are spaced apart from said critical winding ratio lines a distance not less than said reference value;   e) instantaneously increasing the reciprocating speed of the traversing device at the end of each sequential step of the winding cycle when said winding angle reaches said minimum value.   
     
     
       2. The process of claim 1 further comprising setting said maximum value at about 5% greater than said optimum value and setting said minimum value at about 5% less than said optimum value. 
     
     
       3. A device for winding thread from a spinning apparatus in sequential steps in a winding cycle onto a rotating spindle of a collection unit at a constant rate for forming a package, wherein the collection unit comprises a means for rotating the spindle and a traversing device for guiding the thread from the spinning apparatus in reciprocating strokes to the rotating spindle in a winding ratio, wherein the winding ratio represents the ratio of the rotational speed of the package to two of the strokes of the traversing device, and wherein the winding ratio is constant during each step of the sequential steps of the winding cycle and the reciprocating speed of the traversing device increases at the end of each step of the sequential steps of the winding cycle; wherein the device comprises: a) a control unit, wherein said control unit comprises: (1) a process for calculating values for the winding ratios for the collection device and the reciprocating speed of the traversing device during each step of the sequential steps of the winding cycle;   (2) a data storage means for storing operating parameters of the device;,     wherein said operating parameters comprise a reference value, a maximum winding angle, an optimum winding angle, and a minimum winding angle wherein said maximum winding angle and said minimum winding angle area equidistant from said optimum winding angle; (3) a comparator means for comparing said calculated values with said operating parameters; (4) a control signal generating means for generating control signals to the traversing device so that undesirable packages having ribboning are not formed,     wherein said processor, said data storage means, said comparator means and said control signal generating means are all operatively interconnected to one another;     (b) a control keyboard operatively connected to said control unit for entering said operating parameters so that said processor of said control unit processes said operating parameters for determining critical winding ratios, wherein said critical winding ratios form undesirable packages having ribboning and for determining said critical winding ratios closest one another, and wherein said reference value represents a value not greater than half the difference between the closest of said critical winding ratios, so that when said reference value is entered by said control keyboard into said control unit said critical winding ratios are stored in said data storage means;   c) a first detecting means operatively connected to the package and to said control unit for continually detecting the rotational speed of the package and for sending first signals to said control unit;   d) a second detecting means operatively connected to the traversing device and to said control unit for continually detecting the reciprocating speed of the traversing device and for sending second signals to said control unit,   so that when said control unit receives said first and second signals from said first and second detecting means respectively, said control unit compares said first and second signals with said values and said operating parameters stored in said data storage means by said comparator means, and said control signal generating means generates and send control signals for continually controlling the reciprocating speed of the traversing device so that during each step of the sequential steps of the winding cycle a constant winding ratio is maintained, wherein said constant winding ratio is separated from said critical winding ratio by not less than said reference value so that the reciprocating speed of the traversing device increases when the winding ratio reaches said minimum angle at the end of each step of the sequential steps of the winding cycle.